Small Cell Base Station DTX Mode

ABSTRACT

The present disclosure is directed to a system and method for transitioning small cell base stations out of a discontinuous transmission (DTX) mode. The system and method comprise monitoring at the small cell base stations uplink transmissions from user terminals (UTs) to a macrocell base station while the small cell base stations are in the DTX mode. The small cell base stations can use the monitored uplink transmissions to, for example, measure received power levels from the UTs and/or measure uplink path losses between the small cell base stations and the UTs. The small cell base stations can report these measured values back to the macrocell base station through a backhaul network. Based on these measurements, the macrocell base station can determine which small cell base stations can support which UTs without transitioning the small cell base stations out of the DTX mode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/274,328, filed May 9, 2014, which claims the benefit of U.S.Provisional Patent Application No. 61/822,090, filed May 10, 2013, allof which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

This application relates generally to small cell base stations incellular networks.

BACKGROUND

A conventional cellular network is deployed as a homogenous network ofmacrocell base stations. The macrocell base stations may all havesimilar antenna patterns and similar high-level transmit powers. Toaccommodate increases in data traffic, more macrocell base stations canbe deployed in a homogenous network, but such a solution is oftenunattractive due to increased inter-cell interference on the downlinkand due to the high costs associated with site acquisition for newlydeployed macrocell base stations.

Because of these drawbacks, cellular network operators are turning toheterogeneous networks to meet the demands of increased data traffic. Inheterogeneous networks, small cell base stations are used to providesmall coverage areas that overlap with the comparatively larger coverageareas provided by macrocell base stations. The small coverage areas arespecifically provided in areas with high data traffic (or so calledhotspots) to increase capacity. Examples of small cell base stationsinclude, in order of decreasing coverage area, microcell base stations,picocell base stations, and femtocell base stations or home basestations.

One problem with heterogeneous networks is that the addition of smallcell base stations can lead to the cellular network beingoverprovisioned in terms of data traffic capacity during times whentraffic is low. For example, during certain periods of time, many of thedeployed small cell base stations may actually be serving no traffic orsuch a little amount of traffic that a macrocell base station can handlethe traffic while still meeting quality of service (QoS) requirements.In these instances, the small cell base stations are consuming powerthat could otherwise be conserved. Because power costs contribute to alarge percentage of the overall operational costs of running a cellularnetwork, it would be beneficial to turn-off the small cell base stations(or at least portions of the small cell base stations) when they havelittle or no traffic load. In addition, it would be beneficial toturn-off the small cell base stations (or at least portions of the smallcell base stations) when they have little or no traffic load to reducedownlink interference caused by these devices.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate the embodiments of the presentdisclosure and, together with the description, further serve to explainthe principles of the embodiments and to enable a person skilled in thepertinent art to make and use the embodiments.

FIG. 1 illustrates an exemplary heterogeneous cellular network withsmall cell base stations that provide overlapping coverage withmacrocell base stations in which embodiments of the present disclosurecan be implemented.

FIG. 2 illustrates an exemplary high-level block diagram of animplementation of a small cell base station in accordance withembodiments of the present disclosure.

FIG. 3 illustrates a flowchart of a method for a small cell base stationto transition out of the DTX mode in accordance with embodiments of thepresent disclosure.

FIG. 4 illustrates a flowchart of a method for a macrocell base stationto determine which small cell base stations to instruct to transitionout of the DTX mode in accordance with embodiments of the presentdisclosure.

FIG. 5 illustrates a block diagram of an example computer system thatcan be used to implement aspects of the present disclosure.

The embodiments of the present disclosure will be described withreference to the accompanying drawings. The drawing, in which an elementfirst appears is typically indicated by the leftmost digits) in thecorresponding reference number.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the embodiments of thepresent disclosure. However, it will be apparent to those skilled in theart that the embodiments, including structures, systems, and methods,may be practiced without these specific details. The description andrepresentation herein are the common means used by those experienced orskilled in the art to most effectively convey the substance of theirwork to others skilled in the art. In other instances, well-knownmethods, procedures, components, and circuitry have not been describedin detail to avoid unnecessarily obscuring aspects of the disclosure.

References in the specification to “one embodiment,” “an embodiment.”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

I. OVERVIEW

To conserve power and reduce operational costs in a heterogeneouscellular network, small cell base stations that provide overlappingcoverage with a macrocell base station can be turned-off when trafficloads permit. For example, much of the power used by a small cell basestation is consumed by the small cell base station's transmitter used totransmit downlink to user terminals (UTs). At times when there is littleor no data traffic being served by the small cell base station, thetransmitter can be powered down or, in other words, the small cell basestation can be placed in a discontinuous transmission (DTX) mode.

However, when the traffic load increases at the macrocell base stationor at active small cell base stations, at least some of the small cellbase stations that were placed in a DTX mode may need to transition outof the DTX mode to alleviate capacity issues. One way of determiningwhich small cell base stations to transition out of the DTX mode is toturn-on all (or a large number) of the small cell base stations that arein the DTX mode so that the small cell base stations can transmit pilotsignals. UTs in the range of one or more of the small cell base stationsthat are turned-on can perform channel measurements using the pilotsignals transmitted by the small cell base stations and report themeasurements back to the macrocell base station. Based on thesemeasurements, the macrocell base station can determine which small cellbase stations can support which UTs and, from there, select which UTs tohandover to which small cell base stations to alleviate capacity issues.Small cell base stations that receive no UTs during this process canrevert back to the DTX mode.

The above approach to transitioning small cell base stations out of theDTX mode can be inefficient because it can create significantinterference or at least a significant change in interference when all(or a large number) of the small cell base stations are turned-on and itcan require some small cell base stations to transition out of the DTXmode only to revert right back into the DTX mode. In addition, UTs withpoor QoS may search for all small cell base stations under thisapproach, which can result in significant outage time and loss of powerfor those UTs.

The present disclosure is directed to a system and method fortransitioning small cell base stations out of the DTX mode without theseand other inefficiencies. In one embodiment, the system and methodcomprise monitoring, at the small cell base stations, uplinktransmissions from UTs to a macrocell base station while the small cellbase stations are in the DTX mode. The small cell base stations can usethe monitored uplink transmissions to, for example, measure receivedpower levels from the UTs and/or measure uplink path losses between thesmall cell base stations and the UTs. The small cell base stations canreport these measured values back to the macrocell base station througha backhaul network. Based on these measurements, the macrocell basestation can determine which small cell base stations can support whichUTs without transitioning all (or a large number) the small cell basestations out of the DTX mode. From there, the macrocell base station canselect which UTs to handover to which small cell base stations toalleviate capacity issues and transition those small cell base stationsout of the DTX mode. Further aspects of the system and method of thepresent disclosure are described below.

II. EXEMPLARY OPERATING ENVIRONMENT

FIG. 1 illustrates an exemplary heterogeneous cellular network 100 inwhich embodiments of the present disclosure can be implemented.Heterogeneous cellular network 100 can be operated in accordance withany one of a number of different cellular network standards, includingone of the current or yet to be released versions of the long-termevolution (LTE) standard and the worldwide interoperability formicrowave access (WiMAX) standard.

As shown in FIG. 1, heterogeneous cellular network 100 is distributedover macrocells 102-106 that are each served by a respective macrocellbase station 108-112. Macrocells 102-106 are geographically joinedtogether to enable user terminals (UTs) 114 (e.g., mobile phones,laptops, tablets, pagers, smart watches, smart glasses, or any otherdevice with an appropriate wireless modem) to wirelessly communicateover a wide area with a core network 116 via macrocell BSs 108-112.Macrocell BSs 108-112 are coupled to the core network by a backhaulnetwork 118.

As further shown in FIG. 1, macrocells 102-106 are overlaid with severalsmall cells 120-130 that are each served by a respective small cell basestation. The small cell base stations are deployed in areas with highdata traffic (or so called hotspots) to increase capacity. Although notshown, the small cell base stations are further coupled to the corenetwork 116 by backhaul network 118.

Referring now to FIG. 2, an exemplary high-level block diagram 200 of animplementation for one or more of the small cell base stations in FIG. 1is illustrated in accordance with embodiments of the present disclosure.As shown in block diagram 200, the small cell base station includes abackhaul transceiver 202, a baseband processor 204, an RF transceiver206, and at least one antenna 208. RF transceiver 206 further includesan RF transmitter 210 and an RF receiver 212.

In operation, baseband processor 204 can be used to implement, at leastin part, the radio protocol stack for one of several different cellularstandards, including LTE and WiMAX, and can be used as an interface forpassing data between backhaul transceiver 202 and RF transceiver 206.For example, data received over the backhaul network by backhaultransceiver 202 can be passed to baseband processor for formatting inaccordance with a radio protocol stack, such as LTE. The formatted datacan then be passed to RF transmitter 210 to perform, among other things,modulation of the formatted data onto a carrier, up-conversion of thecarrier, amplification using a power amplifier, and transmissiondownlink to a UT served by the small cell base station using antenna208.

Similarly, RF receiver 212 can receive an uplink signal from a UT servedby the small cell base station using antenna 208 and can perform, amongother things, amplification of the received signal using a low-noiseamplifier, down-conversion of a carrier in the amplified signal, anddemodulation of the down-converted carrier to recover data. Therecovered data can be passed to baseband processor 204 to format thedata in accordance with the radio protocol stack before passing the dataon to backhaul transceiver 202 for transmission over the backhaulnetwork. The baseband processor 204 can also transmit, receive, andprocess control messages with its corresponding macrocell base stationas described herein.

III. SYSTEM AND METHOD FOR TRANSITIONING A SMALL CELL BASE STATION OUTOF A DTX MODE

Referring back to FIG. 1, to conserve power and reduce operational costsin heterogeneous cellular network 100, the small cell base stations thatprovide overlapping coverage with macrocell base stations 108-112 can beturned-off when traffic loads permit. For example, much of the powerused by a small cell base station is consumed by the small cell basestation's transmitter, such as RF transmitter 210 in FIG. 2, used totransmit downlink to UTs. At times when there is little or no datatraffic being served by the small cell base station, the transmitter canbe powered down or, in other words, the small cell base station can beplaced in a discontinuous transmission (DTX) mode. The receiver used toreceive uplink transmissions from UTs, such as RF receiver 212 in FIG.2, may also be powered down while the small cell base station is in theDTX mode.

When the traffic load increases at the macrocell base station or even atother active small cell base stations, at least some of the small cellbase stations that were placed in the DTX mode may need to transitionout of the DTX mode to alleviate capacity issues so that QoSrequirements can be met.

The present disclosure is directed to a system and method fortransitioning small cell base stations out of the DTX mode in anefficient manner. Embodiments of the system and method can be explainedusing macrocell base station 108 and the small cell base stations ofsmall cells 120-124 that overlay the coverage area provided by macrocellbase station 108. In this exemplary context, to transition one or moreof the small cell base stations of small cells 120-124 out of a DTXmode, macrocell base station 108 can begin by transmitting, a message tothe small cell base stations via backhaul network 118 to monitor uplinktransmissions to macrocell base station 108 from UTs inside therespective sensing ranges of the small cell base stations.

Upon receiving the message, the baseband processors of the small cellbase stations, such as baseband processor 204 in FIG. 2, may need tofirst power-up the receivers of the small cell base stations used toreceive uplink transmissions from UTs. After the receivers of the smallcell base stations are powered up, the small cell base stations canbegin to monitor uplink transmissions to macrocell base station 108while remaining in the DTX mode.

The small cell base stations can use the monitored uplink transmissionsto measure received power levels from the UTs. For example, the basebandprocessors of the small cell base stations can measure received powerlevels for the monitored uplink transmissions. The small cell basestations can then report the measured received power levels to macrocellbase station 108 via backhaul network 118 using their backhaultransceivers, such as backhaul transceiver 202 in FIG. 2. Macrocell basestation 108 can use the measured received power levels to determinewhether an uplink transmission for a particular UT was received withadequate power at the small cell base station to support at least thesame level of QoS that macrocell base station 108 is providing to the UTin the uplink direction in the event that the UT is handed over to thesmall cell base station. Macrocell base station 108 can make thisdetermination by comparing the measured received power reported by thesmall cell base station to the received power it measures for the sameuplink transmission. In another embodiment, Macrocell base station 108can use the measured received power levels to determine whether anuplink transmission for a particular UT was received with adequate powerat the small cell base station to support a required or minimum QoS inthe uplink direction in the event that the UT is handed over to thesmall cell base station.

In one embodiment, the small cell base stations only measure thereceived powers (or report the measured received powers) for uplinktransmissions that the small cell base stations are able to properlyrecover data from. Verification of proper recovery can be performed, forexample, using a cyclic redundancy check included in the uplinktransmissions. In order to attempt to recover the data transmitteduplink by the UTs to macrocell base station 108, the small cell basestations can further receive from macrocell base station 108 one or moreof the upstream allocations for the UTs (e.g., the uplink time/frequencyresource blocks assigned to each UT), identifying information of the UTs(such as an assigned ID number), and the code rate and modulation orderthe UTs are expected to use to transmit data uplink. The small cell basestation can receive this information from macrocell base station 108over backhaul network 118 or by sniffing downlink transmissions frommacrocell base station 108 to the UTs that contain this information.

The small cell base stations can further use the monitored uplinktransmissions to measure the uplink path loss from the UTs to the smallcell base stations. For example, the baseband processors of the smallcell base stations can use the received pilot tones in the uplinktransmissions and the known transmitted values of those pilot tones tomeasure the uplink path loss from the UTs to the small cell basestations. The small cell base stations can then report the measureduplink path losses to macrocell base station 108 via backhaul network118. Macrocell base station 108 can use the measured uplink path lossesto determine whether the small cell base station can support at leastthe same QoS that macrocell base station 108 is providing to a UT in thedownlink direction in the event that the UT is handed over to the smallcell base station. In another embodiment, Macrocell base station 108 canuse the measured uplink path losses to determine whether the small cellbase station can support a required QoS or minimum QoS in the downlinkdirection in the event that the UT is handed over to the small cell basestation.

For example, macrocell base station 108 can use the uplink path lossmeasured for an uplink transmission from a UT to estimate the downlinkpath loss (given that the two path losses are typically similar) betweenthe small cell base station and the UT. Then, using the estimateddownlink path loss and a transmit power associated with the small cellbase station, macrocell base station 108 can determine whether the smallcell base station can support at least the same QoS that macrocell basestation 108 is providing to a UT. In another embodiment. Macrocell basestation 108 can use the estimated downlink path loss and a transmitpower associated with the small cell base station to determine whetherthe small cell base station can support a required QoS or minimum QoS inthe downlink direction in the event that the UT is handed over to thesmall cell base station.

As explained above, macrocell base station 108 can determine from theinformation reported by the small cell base stations which small cellbase stations can support which UTs with adequate QoS in both the uplinkand downlink directions without transitioning the small cell basestations out of the DTX mode. Based on this knowledge, macrocell basestation 108 can select which UTs to handover to which small cell basestations to alleviate capacity issues and transition those small cellbase stations out of the DTX mode. To transition a small cell basestation out of the DTX mode, macrocell base station 108 can send amessage to the small cell base station to exit the DTX mode. The messagecan be sent over the backhaul network or even over a downlink channel.

In one embodiment, once a small cell base station is instructed to exitthe DTX mode, the small cell base station can power-up its transmitter,such as RF transmitter 210 in FIG. 2.

In a further embodiment, UTs can be instructed by macrocell base station108 to scan only for those small cell base stations that can supportadequate QoS in the uplink and downlink directions to the UTs.

Referring now to FIG. 3, a flowchart 300 of a method for a small cellbase station to transition out of a DTX mode in accordance withembodiments of the present disclosure is illustrated. The method offlowchart 300 can be implemented by a small cell base station configuredas shown in FIG. 2. However, it should be noted that the method can beimplemented by other small cell base stations with differentconfigurations.

The method of flowchart 300 begins at step 302. At step 302, the smallcell base station receives a message over a backhaul network from themacrocell base station that it provides overlapping coverage with. Thesmall cell base station can use backhaul transceiver 202 in FIG. 2, forexample, to receive the message. The message instructs the small cellbase station to monitor uplink transmissions to the macrocell basestation from UTs inside the small cell base station's sensing range.

At step 304, the small cell base station monitors uplink transmissionsto the macrocell base station from the UTs inside the small cell basestation's sensing range while the small cell base station is in the DTXmode. The small cell base station can use RF receiver 212 in FIG. 2, forexample, to monitor the uplink transmissions.

At step 306, the small cell base station measures the received powersassociated with those monitored uplink transmissions and reports thosemeasured received powers to the macrocell base station via the backhaulnetwork. The small cell base station can use baseband processor 204 inFIG. 2, for example, to measure the received powers. In one embodiment,the small cell base station reports to the macrocell base station onlythe received powers associated with those monitored uplink transmissionsthat the small cell base station is able to recover data from asexplained above.

In addition to measuring and reporting the received powers, at step 306the small cell base station can further measure the uplink path lossassociated with the monitored uplink transmissions using, for example,pilot tones transmitted by the UTs in the uplink transmissions. Oncemeasured, the small cell base station can report the measured uplinkpath losses to the macrocell base station via the backhaul network.

At step 308, the small cell base station transitions out of the DTX modeif instructed to by the macrocell base station based on the reportedmeasured received power and/or path loss measurements.

Referring now to FIG. 4, a flowchart 400 of a method for a macrocellbase station to determine which small cell base stations to instruct totransition out of the DTX mode in accordance with embodiments of thepresent disclosure is illustrated. The macrocell base station can havethe same or a similar configuration as that of the small cell basestation shown in FIG. 2.

The method of flowchart 400 begins at step 402. At step 402, themacrocell base station transmits a message to the small cell basestations in a DTX mode to monitor uplink transmissions to the macrocellbase station from UTs inside their sensing ranges.

At step 404, the macrocell base station receives over the backhaulnetwork from the small cell base stations measured received powersassociated with the monitored uplink transmissions. In one embodiment,the macrocell base station only receives the measured received powersassociated with those monitored uplink transmissions that the small cellbase stations are able to successfully decode and verify the data fromas explained above.

In addition to receiving over the backhaul network from the small cellbase stations measured received powers associated with the monitoreduplink transmissions, at step 404 the macrocell base station can receiveover the backhaul network from the small cell base stations measureduplink path losses associated with the uplink transmissions.

At step 406, the macrocell base station can determine from theinformation reported by the small cell base stations which small cellbase stations can support which UTs with adequate QoS in both the uplinkand downlink directions as explained above. From there, the macrocellbase station can select which UTs to handover to which small cell basestations to alleviate capacity issues and, thereby, select those smallcell base stations to transition out of the DTX mode.

At step 408, the macrocell base station can send a message to the smallcell base stations selected at step 406 to transition out of the DTXmode. The message can be sent over the backhaul network or even over adownlink channel.

IV. EXAMPLE COMPUTER SYSTEM ENVIRONMENT

It will be apparent to persons skilled in the relevant art(s) thatvarious elements and features of the present disclosure, as describedherein, can be implemented in hardware using analog and/or digitalcircuits, in software, through the execution of instructions by one ormore general purpose or special-purpose processors, or as a combinationof hardware and software.

The following description of a general purpose computer system isprovided for the sake of completeness. Embodiments of the presentdisclosure can be implemented in hardware, or as a combination ofsoftware and hardware. Consequently, embodiments of the disclosure maybe implemented in the environment of a computer system or otherprocessing system. An example of such a computer system 500 is shown inFIG. 5. Modules depicted in FIG. 2 may execute on one or more computersystems 500. Furthermore, each of the steps of the flowchart depicted inFIGS. 3 and 4 can be implemented on one or more computer systems 500.

Computer system 500 includes one or more processors, such as processor504. Processor 504 can be a special purpose or a general purpose digitalsignal processor. Processor 504 is connected to a communicationinfrastructure 502 (for example, a bus or network). Various softwareimplementations are described in terms of this exemplary computersystem. After reading this description, it will become apparent to aperson skilled in the relevant art(s) how to implement the disclosureusing other computer systems and/or computer architectures.

Computer system 500 also includes a main memory 506, preferably randomaccess memory (RAM), and may also include a secondary memory 508.Secondary memory 508 may include, for example, a hard disk drive 510and/or a removable storage drive 512, representing a floppy disk drive,a magnetic tape drive, an optical disk drive, or the like. Removablestorage drive 512 reads from and/or writes to a removable storage unit516 in a well-known manner. Removable storage unit 516 represents afloppy disk, magnetic tape, optical disk, or the like, which is read byand written to by removable storage drive 512. As will be appreciated bypersons skilled in the relevant art(s), removable storage unit 516includes a computer usable storage medium having stored therein computersoftware and/or data.

In alternative implementations, secondary memory 508 may include othersimilar means for allowing computer programs or other instructions to beloaded into computer system 500. Such means may include, for example, aremovable storage unit 518 and an interface 514. Examples of such meansmay include a program cartridge and cartridge interface (such as thatfound in video game devices), a removable memory chip (such as an EPROM,or PROM) and associated socket, a thumb drive and USB port, and otherremovable storage units 518 and interfaces 514 which allow software anddata to be transferred from removable storage unit 518 to computersystem 500.

Computer system 500 may also include a communications interface 520.Communications interface 520 allows software and data to be transferredbetween computer system 500 and external devices. Examples ofcommunications interface 520 may include a modem, a network interface(such as an Ethernet card), a communications port, a PCMCIA slot andcard, etc. Software and data transferred via communications interface520 are in the form of signals which may be electronic, electromagnetic,optical, or other signals capable of being received by communicationsinterface 520. These signals are provided to communications interface520 via a communications path 522. Communications path 522 carriessignals and may be implemented using wire or cable, fiber optics, aphone line, a cellular phone link, an RF link and other communicationschannels.

As used herein, the terms “computer program medium” and “computerreadable medium” are used to generally refer to tangible storage mediasuch as removable storage units 516 and 518 or a hard disk installed inhard disk drive 510. These computer program products are means forproviding software to computer system 500.

Computer programs (also called computer control logic) are stored inmain memory 506 and/or secondary memory 508. Computer programs may alsobe received via communications interface 520. Such computer programs,when executed, enable the computer system 500 to implement the presentdisclosure as discussed herein. In particular, the computer programs,when executed, enable processor 504 to implement the processes of thepresent disclosure, such as any of the methods described herein.Accordingly, such computer programs represent controllers of thecomputer system 500. Where the disclosure is implemented using software,the software may be stored in a computer program product and loaded intocomputer system 500 using removable storage drive 512, interface 514, orcommunications interface 520.

In another embodiment, features of the disclosure are implementedprimarily in hardware using, for example, hardware components such asapplication-specific integrated circuits (ASICs) and gate arrays.Implementation of a hardware state machine so as to perform thefunctions described herein will also be apparent to persons skilled inthe relevant art(s).

IV. CONCLUSION

Embodiments have been described above with the aid of functionalbuilding blocks illustrating the implementation of specified functionsand relationships thereof. The boundaries of these functional buildingblocks have been arbitrarily defined herein for the convenience of thedescription. Alternate boundaries can be defined so long as thespecified functions and relationships thereof are appropriatelyperformed.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the disclosure that others can, by applyingknowledge within the skill of the art, readily modify and/or adapt forvarious applications such specific embodiments, without undueexperimentation, without departing from the general concept of thepresent disclosure. Therefore, such adaptations and modifications areintended to be within the meaning and range of equivalents of thedisclosed embodiments, based on the teaching and guidance presentedherein. It is to be understood that the phraseology or terminologyherein is for the purpose of description and not of limitation, suchthat the terminology or phraseology of the present specification is tobe interpreted by the skilled artisan in light of the teachings andguidance.

What is claimed is:
 1. A method for transitioning a small cell basestation out of a discontinuous transmission (DTX) mode, the methodcomprising: monitoring, at the small cell base station, an uplinktransmission to a macrocell base station from a user terminal (UT) whilethe small cell base station is in the DTX mode; reporting, to themacrocell base station, a measured received power associated with theuplink transmission and an uplink path loss measurement associated withthe uplink transmission; and transitioning the small cell base stationout of the DTX mode if instructed to by the macrocell base station basedon the reported measured received power associated with the uplinktransmission and the reported uplink path loss measurement associatedwith the uplink transmission.
 2. The method of claim 1, wherein themonitoring is performed based on a traffic load condition at themarcocell.
 3. The method of claim 1, wherein the monitoring is performedif the macrocell base station is unable to handle a traffic load at arequired quality of service level.
 4. The method of claim 1, furthercomprising: receiving from the macrocell base station a UTidentification, an uplink resource allocation, a code rate, and amodulation scheme to be used by the UT to transmit the uplinktransmission.
 5. The method of claim 4, wherein the UT identification,the uplink resource allocation, the code rate, and the modulation schemeare received from the macrocell base station over a backhaul network. 6.The method of claim 4, wherein the UT identification, the uplinkresource allocation, the code rate, and the modulation scheme arereceived from the macrocell base station via a downlink transmission tothe UT.
 7. The method of claim 4, further comprising: decoding theuplink transmission using the uplink resource allocation, the code rate,and the modulation scheme to verify that the small cell base station isable to properly decode the uplink transmission.
 8. The method of claim1, wherein the measured received powers associated with the uplinktransmission are determined based on pilot signals sent by the UT in theuplink transmission.
 9. The method of claim 1, wherein the macrocellbase station uses the reported measured received power associated withthe uplink transmission to determine whether the small cell base stationis able to support a quality of service level in the uplink directionfrom the UT to the small cell base station.
 10. The method of claim 1,wherein the macrocell base station uses the reported path lossmeasurement associated with the uplink transmission to determine whetherthe small cell base station is able to support a quality of servicelevel in the downlink direction from the small cell base station to theUT.
 11. A small cell base station, comprising: a receiver configured tomonitor an uplink transmission to a macrocell base station from a userterminal (UT) while the small cell base station is in a discontinuoustransmission (DTX) mode; and a baseband processor configured to reportto the macrocell base station a measured received power associated withthe uplink transmission and uplink path loss measurement associated withthe uplink transmission.
 12. The small cell base station of claim 11,wherein the baseband processor is further configured to transition thesmall cell base station out of the DTX mode if instructed to by themacrocell base station based on the reported measured received powerassociated with the uplink transmission and the reported uplink pathloss measurement associated with the uplink transmission.
 13. The smallcell base station of claim 11, further comprising: a transmitterconfigured to transmit downlink to the UT, wherein the basebandprocessor is configured to transition the small cell base station out ofthe DTX mode by powering up the transmitter.
 14. The small cell basestation of claim 11, wherein the receiver is powered down prior tomonitoring the uplink transmission.
 15. The small cell base station ofclaim 11, wherein the receiver monitors the uplink transmission based ona traffic load.
 16. The small cell base station of claim 11, wherein thereceiver is further configured to receive from the macrocell basestation a message comprising a UT identification, an uplink resourceallocation, a code rate, and a modulation scheme to be used by the UT totransmit the uplink transmission.
 17. The small cell base station ofclaim 11, wherein the receiver is further configured to receive from themacrocell base station via a downlink transmission to the UT a UTidentification, an uplink resource allocation, a code rate, and amodulation scheme to be used by the UT to transmit the uplinktransmission.
 18. A method for transitioning a small cell base stationout of a discontinuous transmission (DTX) mode, the method comprising:monitoring, at the small cell base station, an uplink transmission to amacrocell base station from a user terminal (UT) while the small cellbase station is in the DTX mode; reporting, to the macrocell basestation, a measured received power associated with the uplinktransmission based on the small cell base station properly decoding theuplink transmission; and transitioning the small cell base station outof the DTX mode if instructed to by the macrocell base station based onthe reported measured received power associated with the uplinktransmission.
 19. The method of claim 18, wherein the monitoring isperformed based on a traffic load.
 20. The method of claim 18, whereinthe macrocell base station uses the reported measured received powerassociated with the uplink transmission to determine whether the smallcell base station is able to support a quality of service level in theuplink direction from the UT to the small cell base station.